Go to Tools menu > Preferences > Fees tab and check “Edit Fees Manually”. Now on the send tab you will find a field next to the fee slider where you can enter the absolute amount in fees you want to pay.
Calculating an appropriate fee
Fees depend on the size of your transaction in bytes. You can find out the size of your transaction by clicking on preview on the send tab. It’ll display a window like the one below with your transaction size listed:
As you can see the above transaction is 192 bytes.
Next you need to know what the prevailing fees are. You can find that out here. The fees are listed in terms of satoshis per byte. If you’re trying to save money I suggest ignoring the bars at top and look at the bunched up bars at the bottom.
Assuming you decide on 100 satoshis/byte fee this is how much a 192 bytes transaction is going to cost you in terms of bitcoin:
(100 * 192)/100,000,000 = 0.000192 btc
(That’s 100 satoshis per byte into 192 bytes and then the whole thing is divided by 100 million which is the number of satoshis in a bitcoin)
So you would enter 0.000192 in the field next to the fee slider.
I also recommend checking “Replaceable” on the send tab. This will allow you to low ball the fee and bump it later on if the transaction doesn’t confirm in a timely manner. If you don’t see the replaceable option on the send tab go to Tools menu > Preferences > Fees tab and select “Always” for the “Propose Replace-By Fee” option.
What makes my transaction so large?
The size of your transaction determines the fee. The number of inputs and outputs determines the size of your transaction. If you regularly received small amounts of money from faucets or mining pools in the past your transaction would be very large because of the large number inputs so you would pay a relatively high fee.
I’m really cheap. Tell me how I can save even more money?
- Check “Replaceable” on the send tab so that you can bump the fee later on if you need to. This also allows you to low ball the fee initially.
Save the signed transaction to file so that you can rebroadcast it again if you need to. Low fee transactions get ejected from nodes’ mempools when they encounter higher paying transactions. Rebroadcasting them brings to the nodes’ attention again.
To save the transaction right click on the transaction on the history tab, choose “Details” and then click save. You can also do this on the send tab where instead of clicking send you click on preview > sign > save and then click broadcast to send
If the transaction disappears from the Electrum history tab then you know that it has been ejected from the mempool of the electrum server you are connected to and it is time to rebroadcast it. You can do that by going to Tools menu > Load Transaction > From File and select the saved transaction. Then click on broadcast to broadcast it again.